Waterjet cutting systems produce high pressure, high-velocity jets of water for cutting materials. These systems typically function by pressurizing water or another suitable fluid to a high pressure (e.g., up to 90,000 pounds per square inch or greater) and forcing the fluid through a small orifice at high velocity to concentrate a large amount of energy on a small area. To cut hard materials, a water jet can be “abrasive” or include abrasive particles within the water jet for increasing cutting ability. As used herein, the term “waterjet” includes any substantially pure water jet, liquid jet, and/or slurry jet. As used herein, the term “pump” means “ultra-high pressure pump” between about 30,000-90,000 pounds per square inch (PSI) or above. However, one of ordinary skill in the art could easily appreciate that the invention also applies to low pressure systems.
During operation of waterjet cutting systems, fluid (e.g., water) is directed to a waterjet orifice assembly for constriction and alignment by the waterjet orifice assembly. The water stream exiting the orifice assembly must be well-aligned to an axis of the waterjet nozzle such that the water stream does not significantly touch the interior wall of the nozzle prior to exiting the cutting head. It is preferable for the water stream to be centered within the nozzle. Poor water stream alignment will cause the nozzle life and cut performance (e.g. cut speed, part tolerance and edge quality) to deteriorate. Currently, orifice assemblies are built by placing an orifice in a cavity of a machined base or housing and then pressing a retaining ring over the orifice to secure the orifice in place. However, using this approach it can be difficult to machine the cavity to the high level of accuracy that is required for excellent alignment of the orifice stream to the axis of the nozzle. Orifice assemblies can also be manufactured by assembling the orifice into a base blank; aligning the water stream exiting the blank; and machining the orifice assembly datum features accordingly to achieve proper alignment. However, this process can be very costly, and it can have difficulty achieving high water stream alignment. What is needed is a well-aligned orifice assembly that can be produced consistently without a costly alignment procedure.